The difficulty in displaying or representing long, hierarchically structured lists may be encountered nowadays in many technical fields, such as for the display of hierarchically structured lists on the display element of a computer system or on a navigation display. In this regard, a navigation system is used as an example below.
In a navigation system for displaying the results of a route search, a list of names of the streets included in the route may be generated. In addition to the actual street names (shown in Roman numerals in FIG. 1), the entries may also contain any existing street numbers (shown in Arabic numerals in FIG. 1) and the town (shown in capital letters in FIG. 1) to which the streets belong (see FIG. 1).
Although the “flat” or non-hierarchical display shown in FIG. 1 may be used in this form, it may be considered generally impracticable and not clear. For greater practicability and better clarity, entries and elements which are associated with a specific town (shown in capital letters in FIGS. 1 and 2) or a specific street number (shown in Arabic numerals in FIGS. 1 and 2) may be combined and hierarchically displayed, as illustrated in FIG. 2.
This form of the tree display shown as an example in FIG. 2 may offer the user greater practicability and better clarity, since the various entries and elements are displayed in a weighted manner according to their importance. It may also be possible to combine the partial lists created, also referred to below as “subordinate lists” or “sublists,” and to display them using only the superordinate entry or the superordinate element.
Thus, for example, the streets within towns may be concealed so that the route list appears as a list of towns with overland road connections (see FIG. 3). Such a display may be practical, for example, for long cross-country trips for which the individual streets in the towns may be of no concern.
To show an existing possibility for expanding a concealed branch of the hierarchically structured list, a square with a plus sign has been established. Accordingly, a square with a minus sign is displayed for the existing possibility of collapsing a subordinate list or sublist. One such example is the route list displaying all towns and streets including street numbers, as shown in FIG. 4.
In addition to these various preset lists in which only certain portions are shown or concealed, other configurations may also be possible. Thus, after interaction with the user it may be possible to expand some sublists and to combine others (see FIG. 5).
The possibility of combining or collapsing sublists, or also expanding these sublists, is intended to help the user obtain a better overview of the information provided. This may be important since the display possibilities in navigation devices for an arrangement for transport, for example, may be limited by a small display. Thus, some conventional navigation devices, even those for a high-end arrangement for transport, may provide, for example, only six lines for displaying the list of street names.
Using an example of a display having ten lines, the hierarchically structured list and the corresponding display window are shown in FIGS. 6A and 6B. The entries and elements in boldface in FIGS. 6A and 6B appear in the display window, whereas the entries and elements in lighter typeface located outside the display window are used only for better understanding of the relationships, but are not visible to the user in the display window.
However, as seen from a comparison of FIGS. 7A and 7B, there may be an undesired feature for hierarchically structured lists, in that for specific regions it may not be possible to determine a direct association of the street name with the street number or with the town, or to determine a direct association of the street number with the town. This effect may appear, for example, in the middle of long subordinate lists.
In this case, the user may only obtain the sought information by scrolling through the hierarchically structured list. For very long lists this procedure may be undesired and impracticable because the actual entry or element of interest may be lost from the field of vision during scrolling. Thus, only in relatively few cases may it be possible to see the relevant entries and elements simultaneously. Thus, using FIG. 7B as an example, it is not possible to directly determine that street name IX belongs to town B. A direct association may therefore not always be possible, which may be perceived as unsatisfactory in light of the accompanying loss of information.
The display of hierarchically structured lists may generally be affected by this undesired feature when it is not possible to completely display these lists in the display medium (for the most part, it may not be possible to completely display hierarchically structured lists in the display medium; see FIG. 8A).
An example in the field of computer technology may include the display of file managers, such as for example in the case of Explorer in the Windows® operating system by Microsoft®. For such applications, it may not be possible in some cases for the user to, for example, determine what the superordinate directory, or even the superordinate directories of the files or directories instantaneously shown in the display window, are (see FIG. 8B).